Magic Lantern Forum

Using Magic Lantern => General Help Q&A => Duplicate Questions => Topic started by: basovandrey on February 16, 2013, 08:58:21 AM

Title: [WONTFIX] New OVERLAY (DOF)
Post by: basovandrey on February 16, 2013, 08:58:21 AM
Hello.
Propose to make a new mode overley DOF.
(http://rghost.ru/private/43831101/35a6452d25ebbbddac046fbb0d7b723b/image.png) (http://rghost.ru/private/43831101/35a6452d25ebbbddac046fbb0d7b723b.view)
(http://rghost.ru/43831211/image.png) (http://rghost.ru/43831211.view)
Draw directly on the screen LiveView line and DOF Near DOF Far.
Formula and sketch here. https://docs.google.com/spreadsheet/ccc?key=0Ar2tmqEUFi2vdC1nOWNPekNOUG02dEJhVVhwcjNsdXc&usp=sharing
I spread scans of as I did the calculation.
Sorry I do not speak English.

(http://rghost.ru/43831053/thumb.png) (http://rghost.ru/43831053.view) (http://rghost.ru/43831060/thumb.png) (http://rghost.ru/43831060.view) (http://rghost.ru/43831064/thumb.png) (http://rghost.ru/43831064.view)
Title: Re: New OVERLAY (DOF)
Post by: Michael Zöller on February 16, 2013, 05:00:37 PM
If this can actually be done in a more or less reliable way... wow!
Title: Re: New OVERLAY (DOF)
Post by: g3gg0 on February 16, 2013, 05:34:52 PM
problem is the focal length that cannot be measured reliable.
some lenses report it, some not and the report is unreliable iirc.
Title: Re: New OVERLAY (DOF)
Post by: a1ex on February 16, 2013, 07:25:53 PM
What's the use for this?!
Title: Re: New OVERLAY (DOF)
Post by: Francis on February 16, 2013, 08:21:09 PM
Interesting, but way more going on than could be easily calculated in camera.

How would the camera know where to draw the lines. This would be dependent not just on the focal distance but where the plane of focus falls on the image. How would the camera know if you were completely parallel to a flat surface like a wall, in which the entire image is in focus?

Besides, focus peaking already does the job.
Title: Re: New OVERLAY (DOF)
Post by: wolf on February 17, 2013, 12:23:12 AM
The lenses for Hasselblad cameras have a mechanical calculation for the DOF.
I think for filming it's interesting to know the area or the distances exactly were everything is in focus.
But to draw 3D orientated lines in LV is a high goal IMHO.  :-)

(http://upload.wikimedia.org/wikipedia/commons/thumb/f/fc/Hasselblad_with_Planar_80mm_at_EV_12.jpg/220px-Hasselblad_with_Planar_80mm_at_EV_12.jpg)
Title: Re: New OVERLAY (DOF)
Post by: sonus on February 17, 2013, 02:38:11 AM
The electronic level in some cameras could provide a guide for some kind of 3d plane.
Seems like it would be near impossible to pull off, but would be useful for some.
Title: Re: New OVERLAY (DOF)
Post by: discocalculi on February 17, 2013, 11:21:08 AM
Interesting idea, but there's already a similar feature and that's focus peaking.

Although it looks different on the live view, it works pretty much in the same way. If the aperture of the lens is closed down, the focus peaking also shows it.
Title: Re: [WONTFIX] New OVERLAY (DOF)
Post by: basovandrey on February 17, 2013, 03:49:24 PM
Add.
You can calculate the projection angle to the ground plane in the camera screen. But the formula is not yet designed.
You can see here. https://docs.google.com/spreadsheet/ccc?key=0Ar2tmqEUFi2vdC1nOWNPekNOUG02dEJhVVhwcjNsdXc&usp=sharing
Examples.
(http://rghost.ru/43869583/image.png) (http://rghost.ru/43869583.view) (http://rghost.ru/43869600/image.png) (http://rghost.ru/43869600.view)
Title: [WONTFIX] New OVERLAY (DOF)
Post by: Francis on February 17, 2013, 07:47:48 PM
Even using the electronic level, the distance, and FOV to calculate the plane, you are working under the big assumption that your XY plane has no pitch or irregularities, essentially that it is a flat, level floor. Focus peaking is less discriminating.

This could be useful for aerial photography/cartography for someone who isn't using a view camera and the Scheimpflug principle. But then you could just use the hyperfocal distance and correct perspective in post.
Title: Re: [WONTFIX] New OVERLAY (DOF)
Post by: scrax on February 18, 2013, 02:59:09 AM
I don't get it in full, but to me if possible seems more clear than focus peaking.
Maybe is because of the example posted, but if the dof lines are draw on the floor one can figure out if a vertical thing is in focus even if it crosses focus lines, no?

But I think that g3gg0 is right, if we use the lens focal distance it will be unreliable, a graphical DOF preview in Overview option could be better, to simulate what wolf sad about Hasselblad lenses